11.3.2 A dialog which is window-modal on Cocoa

To create a dialog which is window-modal on Cocoa, call the dialog function inside the macro
with-dialog-results
as in this example:

(with-dialog-results (symbol okp)

(prompt-for-symbol

"Enter a class-name symbol:"

:ok-check #'(lambda (symbol)

(find-class symbol nil)))

(when okp

(display-message "symbol is ~S" symbol))
)

On Microsoft Windows, GTK+ and Motif this displays the dialog, calls
display-message
when the user clicks
OK
, and then returns. The effect is no different to what you saw in Prompting for Lisp objects.

On Cocoa, this creates a sheet and returns.
display-message
is called when the user clicks
OK
. The sheet is window-modal, unlike the sheet you saw in Prompting for Lisp objects.

For more details, see the page for
with-dialog-results
in the
LispWorks CAPI Reference Manual
.